http://vww6ybal4bd7szmgncyruucpgfkqahzddi37ktceo3ah7ngmcopnpyyd.onion/en/about-us/newsletter/2012/03
One of the biggest is that the large quantities of viruses, trojans, back-door programs, security bugs, targeted government hacking, and other exploits over the years make them very difficult to trust, especially because you are not given the opportunity to look under the hood to see if what is going on is ok.